RED/AE Workflow for greenscreen

I just got 4K material from a Red Epic Dragon and need to sync the external recorded audio key out the green and track the motion.
On the software side I'm stuck with Adobe CC and the machine is an older iMac. :-/
Now I'm wondering about the best workflow. Im working with RED for the first time so these might be noob questions...
We are only talking about a couple of shots here.

I would definitely render 1080p Proxies for deciding on the take.
Besides that, should I work natively on the R3D files in AE? Can I still get all of the color information in AE? Or do I need to render some DPX sequences from RedCine X-Pro? How about that second file I have in my take folders? How about performance?
And should I do the tracking on the 4K material or would it be enough to do it on the 1080p proxies?

Thanks for your reply.
My first impulse also was to do it in Redcine. And as far as I understand gamma I could always undo it with a reversed curve...(?)
AE should be CC 2015 or so, but I could also update to the newest version, I guess.

For syncing, I would do it in Premiere and you should be able to do it with the RAW files depending on how old your machine is. You may have to reduce the quality in Premiere to half but it should still play well. I can play 8K RED Raw files in real time on my iMac in Premiere. Once you have what you like then send it to After Effects to Key it. That is what I have been doing.

Another option as mentioned is to just convert your files to HD clips in Redcine and then work with them as normal. I'm assuming your final output is HD so I would say no need for Proxies.